Airborne diatomic halogen gases, such as F2, Cl2, Br2, and I2, or halogen comprising gas compounds (e.g., HCl, NF3, SiF4, C2F6, and HF), and activated species thereof, are known to cause corrosion on metal leads of semiconductor devices, or on certain metal layers or metal layer stacks, which can result in yield loss. In a high purity setting, halogens can contaminate a highly controlled atmosphere. What is needed is a methodology and sensing apparatus that can detect halogen comprising gases at lower levels and/or faster than known methods and apparatus/systems.